The present invention relates to an end plate of a fuel cell including a gas-liquid separator. The gas-liquid separator draws emission from a fuel cell unit into a housing and separates water from the emission. The gas-liquid separator then drains the separated water out of the housing.
A fuel cell device includes a fuel cell stack including a fuel cell unit and two end plates (refer to, for example, Japanese Laid-Open Patent Publication No. 2014-44797). The fuel cell unit is formed by stacking cells. The fuel cell unit is held between the two end plates in the stacked direction of the cells.
The fuel cell stack described in the publication includes passages for fuel gas (e.g., hydrogen) and oxidation gas (e.g., air) that are supplied to the fuel cell unit. The fuel cell stack also includes emission passages for draining surplus fuel gas and oxidation gas out of the fuel cell unit. The fuel gas emission passage includes a gas-liquid separator that draws in the fuel gas emitted from the fuel cell unit (hereafter, referred to as the emission) and separates water from the emission. The gas-liquid separator is coupled to an outer surface of one of the end plates via a pipe. The water, which is separated from the emission by the gas-liquid separator, is drained out of the housing from a drain valve and collected in a dilution box.
In Japanese Laid-Open Patent Publication No. 2014-44797, the gas-liquid separator projects out of the end plate. Thus, if the ambient temperature falls to the freezing temperature when the fuel cell device is not operating, the water vapor in the emission may condense and the condensed water may freeze. The frozen condensed water may cause the drain valve to become stuck. As a result, when the fuel cell device restarts operation, the stuck valve may hinder the drainage of water out of the housing.
It is an object of the present invention to provide an end plate for a fuel cell that limits situations in which a drain valve, which drains water out of a housing, becomes stuck at an early stage due to the freezing of condensed water.
To achieve the above object, an end plate arranged on one end of a fuel cell unit includes a plate body and a gas-liquid separator. The plate body is formed from a metal material. The gas-liquid separator includes a housing into which emission from the fuel cell unit is drawn in. The gas-liquid separator separates water from the emission and drains the separated water out of the housing. The housing is formed from a resin material and is in contact with the plate body.
In this structure, the housing of the gas-liquid separator is in contact with the plate body. This effectively transfers the heat of the fuel cell unit to the housing and impedes cooling of the housing by the ambient air. Thus, the temperature of the housing gradually decreases after the fuel cell device stops operating. This limits early condensation of the water vapor in the emission, which, in turn, limits early freezing of the condensed water.